Christchurch mother Cheryl Wilson woke up today not knowing if her daughter will still be alive tomorrow.

Shylah Harwood, 14, has spent more of her life in hospital than out because of an extremely rare disease called Takayasu's arteritis - a form of vasculitis which causes her main arteries to become inflamed.

There are only two other known cases in New Zealand; it puts sufferers at high risk of heart attack and stroke.

"The first year of her life, it was basically spent in Dunedin Hospital, so right from birth it's been ongoing," Wilson said.

"It's been hundreds [of hospital visits] and it's never just for a day or two days, it's weeks or months."

Despite never knowing how each day will end, Shylah and her mother refuse to be upset or angry about their situation.

Shylah was diagnosed after suffering a "warning" heart attack at the age of 9.

"She got such severe chest pain that she was actually ripping the skin off her chest," Wilson said.

Doctors determined Shylah had been living with the disease since she was at least 2, but did not know if she was born with it.

"She's always been a sickly person. She had lots of allergies as a baby, she was allergic to everything. She wasn't on food until 15 months old because she'd react to everything.

"They've got no idea of the cause. It's just something in the makeup, I suppose. It's not one of those things I really want to know."

Shylah had tried every treatment available, including "massive doses" of steroids and chemotherapy. The side effects were extreme. One drug caused her to lose her two front teeth and others weakened her bones until they resembled those of an elderly woman.

Wilson said Shylah suffered chronic pain, but rarely complained.

"Her pain threshold is very high, so when she starts to say she's in pain you know it's bad. The doctors will ask her how she's doing and she'll have tears streaming down her face, but she'll say ‘I'm OK'."

The hardest thing was never knowing what was around the corner, Wilson said.

"It's just changing day by day. Some days are just really touch-and-go. Four times we've been told to get family and friends to visit."

The last time that happened was in July, when Shylah was flown to Auckland's Starship children's hospital because her aorta had narrowed to only 2.7 millimetres. It should have been 12mm to 14mm wide.

She underwent surgery to have metal stents put in her arteries, but it was only a temporary fix until she was stable enough to undergo bypass surgery.

Little was known about Shylah's condition in New Zealand and Wilson sought support from overseas websites.

Her dream was to get Shylah to a specialist vascular clinic in the United States - if she was ever stable enough to handle a long-haul flight.

Money was also an issue, with the family worried especially about their living situation.

It was still not known if their earthquake-damaged house would be repaired or demolished, and they could not afford to pay more than the $330 they currently spent on rent.

Wilson was unable to work because she had to spend so much time in hospital with Shylah, but her unemployment benefit was cut over the Christmas period when she did not attend a work seminar.